Apparatus for coating articles

ABSTRACT

A conveyor for conveying disc like articles past a spraying station. The conveyor comprises a roller, link chain having a first flight extending along one side of a path for the articles, with articles being fed between adjacent pairs of rollers. A spring bar is positioned in a fixed location adjacent the opposite sides of the path to continually force the articles in tangential contact with the pairs of rollers. The spring bar also acts as a friction surface so that driving the flight of the chain along the path will move the articles past the spraying station and will simultaneously rotate the articles. The spraying station includes one spray head, a substantially rectangular spray pattern having a length greater than the diameter of the objects or articles and a second dimension substantially less than the diameter of the articles to prevent spraying of the chain and backing member.

United States Patent Stepenske et al.

[151 3,677,226 [4 1 July 18,1972

APPARATUS FOR COATING ARTICLES Primary Examiner-John P. McIntosh [72] Inventors: Lawrence D. Stepenske; Edward K. Cassldy, both of Chicago, in. Dheny [73] Assignee: National Can Corporation, Chicago, Ill.

22 Filed: Sept. 8, 1970 [57] ABSIRACT A conveyor for conveying disc like articles past a spraying sta- [21 1 Appl' 7o153 tion. The conveyor comprises a roller, link chain having a first flight extending along one side of a path for the articles, with U.S. Cl. 1 1 articles being fed between adjacent of r ner A rin [5 1 1 Int. Cl- ..B05c bar is positioned in a fixed location adja ent the o it id [58] Field of Search ..118/322, 324, 70, 314, 315; f the path to cominually force the articles in tangential com 134/125 126; 198/183 tact with the pairs of rollers. The spring bar also acts as a friction surface so that driving the flight of the chain along the References Cited path will move the articles past the spraying station and will simultaneously rotate the articles. The spraying station in- UNHED STATES PATENTS cludes one spray head, a substantially rectangular spray pat- 570,538 1 1/1 896 Burns ..1 18/322 X {em having a'length greater than the diameter ofthe objects or 2,124,010 l 933 Smith et UX articles and a second dimension substantially less than the 2,154,344 1939 HaTke-T at 118/322 UX diameter of the articles to prevent spraying of the chain and 2,579,737 12/1951 Giordano ..11s/322 x backing memben 2,732,315 l/l956 Birkland ..l l8/322 X 3,452,714 7/1969 Burke et al ..1 18/322 X 10 Claims, 7 Drawing Figures 1a 14 16 H I] 4 1 (I 22, 4', O t 30 um/ \1 Bz 72 78. 74 \3 IH a o- "e 1mm, ml; H {g 7 2 um, 70 NW. r :1 r I I v 4 u I0 Patented July 18, 1972 3 Sheets-Sheet 1 NP A M M W Patented July 18, 1972 3 Sheets-Sheet 2 Patented July 18, 1972 3,677,226 I 3 Sheets-Sheet 5 FIG; 7 f 7 T I00 H 12 HI lll/ APPARATUS FOR COATING ARTICLES BACKGROUND OF THE INVENIION The present invention relates generally to coating or spraying apparatus, and more particularly to an apparatus for coating articles.

In the formation of containers, such as sofi drink or been cans, the container ends for many years have been formed from a precoated metal sheet with the container ends subsequently being attached to the main body of the can or container through the use of a double seam. However, with the advent of the pull tab container, the formation of the score line on the container end which outlines the pull tab for the container end results in exposing the metal. Thus, it has become necessary to further coat the container end with an anti-corrosion material to prevent contamination of the contents in the can through the direct contact of the metal forming the container.

While apparatus for coating container ends has been known for years, the production rates for coating articles with apparatus heretofore known is considerably restricted because the operation is generally performed on an intermittent basis. Thus, in many instances, the container end is moved into alignment with a spray head and the movement thereof is interrupted while a pattern of spray is directed to the container end. In other instances, it has been proposed to rotate the container end while the spray is being applied thereto. Such an arrangement is disclosed in U.S. Pat. No. 1,198,020. However, such an arrangement requires complicated mechanism for starting and stopping the movement of the container ends and also requires additional controls for operating the spraying mechanism on an intermittent basis.

An additional problem encountered in an apparatus of the type disclosed in the above patent is that a pattern of the spray head must be large enough to cover the entire area of the container end. With an arrangement of this type, the supporting and conveying mechanism is subjected to the spray pattern as each container end is sprayed at the coating station and necessitates frequent interruption of the operation to allow for the cleaning of the conveying and supporting mechanism.

SUMMARY OF THE INVENTION The present invention contemplates a simple and effective apparatus for coating container ends that can be operated on a continuous basis thereby eliminating the need for complicated controls heretofore utilized in connection with spraying or coating articles of this type.

Thus, the present invention contemplates the production of a continuous pattern of spray at a coating station, and continuously moving and rotating the articles through the spraying station by contacting the respective articles with a pair of rotating elements at circumferentially spaced locations along one side of the path of movement of the articles and engaging the articles with an elongated stationary backing member along an opposite side of the path. The rotatable elements are moved longitudinally of the stationary member to thereby simultaneously move the articles along the path and rotate the articles while being moved.

The above arrangement allows for the use of a small spray pattern between the backing member and the rotating elements so that the backing member and rotating elements are not subjected to the spray pattern. Such an arrangement considerably increases the operating time before it is necessary to shut down the apparatus for cleaning.

In its preferred embodiment, the method contemplates producing a substantially rectangular spray pattern at the coating station in which one dimension of the spray pattern is substantially less than the spacing between the backing member and the rotatable elements, fonning part of a well I known roller, link chain, and the second dimension of the spray pattern being greater than the diameter of the circular disc like articles to be coated.

The apparatus for performing the above method includes an endless roller, link chain having a flight extending along one side of the path of movement for a plurality of substantially flat circular articles. A backing or biasing member is located on the opposite side of the path and acts to force the container ends between adjacent pairs of rollers on the chain. Articles are sequentially fed in timed relation to one end of the path so as to locate each article between an adjacent pair of rollers and the roller, link chain is continuously driven to move each article through a spraying station. The spraying station is defined by a pair of spray heads spaced along the path and located above the path with the spray heads producing the substantially rectangular spray pattern directed to an open area between the backing member and the driven flight of the roller, link chain. With this arrangement, a coating material is not in any way directed towards the conveyor thereby considerably lengthening the time of operation before cleaning is required.

According to a further aspect of the present invention, the conveyor further has wiper means in the form of a continuous guide surface which cooperates with each roller during each cycle of revolution of the endless chain to prevent accumulation of coating or fluid material at any particular location on the rollers. The mechanism further includes means for restricting the movement of the articles in a direction normal to the path.

According to a still further aspect of the present invention, the roller, link chain and the guide means as well as a drive sprocket forming part of the drive means are incorporated into a self-contained unit which is attached to a frame forming part of the coating mechanism in a manner that the entire unit can be removed and replaced in a matter of seconds. By having a plurality of self-contained units, one unit may be removed for cleaning while a second unit is being utilized in the coating machine.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF DRAWINGS FIG. 1 discloses a coating mechanism having the invention incorporated therein; I

FIG. 2 is a vertical sectional view taken generally along lines 2-2 of FIG. 1;

FIG. 3 is an enlarged plan view of the coating station forming part of the mechanism shown in FIG. 1;

FIG. 4 is an enlarged vertical transverse sectional view taken generally along lines 4-4 of FIG. 1;

FIG. 5 is an enlarged fragmentary sectional view taken generally along lines 5-5 of FIG. 1;

FIG. 6 is a further sectional view taken along lines 6-6 of FIG. 5; and

FIG. 7 is a vertical sectional view taken generally along lines 7-7 of FIG. 1.

DETAILED DESCRIPTION While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail one specific embodiment, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated.

FIG. 1 of the drawings discloses an article coating mechanism generally designated by the reference numeral 10. The article coating mechanism consists of a frame structure 12 having an opening 14 with a hood 16 extending upwardly above the frame to enclose the area surrounding the opening. The hood may be suitably vented through a duct .18 to withdraw any fumes emanating from the coating or spraying station 20 defined by the enclosed area. A pair of spray heads 22 are suitably supported within the enclosure 16 on an extension (not shown) of the frame 12 to produce patterns of spray, generally designated by the reference numeral 24. The details of the spray patterns 24 will be described in detail hereinafter.

While two adjacent spraying stations are contemplated, since they are identical in construction, only one will be described in detail.

According to the present invention, a plurality of articles 30 are sequentially fed from a stack 32 to a path (designated by the arrow of FIG. 1) -extending through the spraying station 20 below the spray head 22. A conveyor constructed in accordance with the present invention is capable of continuously moving the articles along the path and simultaneously rotating the articles as they pass through the spray patterns 24. The conveyor is constructed in a manner that all of the parts of the conveyor are spaced from the spray pattern thereby considerably increasing the amount of operation time before it becomes necessary for cleaning the components of the conveyor.

The conveyor of the present invention is more clearly illustrated in FIGS. 3 and 4 and includes an endless roller chain 34 having one flight 36 extending along one side of the path of movement of the articles through the spraying station. An inspection of FIG. 1 shows that the flight 36 is located on one side of the opening 14, for a purpose which will be described later. The roller, link chain includes a plurality of rollers 38 which are interconnected by links 40 in a manner that the peripheries of the rollers are spaced from each other by a predetermined dimension. The flight 36 of the endless chain 34 is continuously moved in a direction generally parallel to the path of movement of the articles by drive means, which will be described later.

According to one aspect of the invention, the endless chain 34 forms part of a self-contained unit that is attached to the frame 12 by a quick release connection. For this purpose, the endless chain 34 is supported between upper and lower plates 42 and 44 which have first and second spaced guide means 46 and 48 interposed between the plates at opposite ends thereof. The endlesschain 34 is entrained around the guide means 46 and 48 and the peripheries of the rollers 38 are in contact with arcuate surfaces 50-defined on the respective guide means. The self-contained unit further includes a spacer plate 52 located between the guide means 46 and 48 adjacent the flight 36. The spacer plate 52 has a friction element 54 secured to one surface thereof and located in a position that the peripheries of the respective rollers 38 are in constant engagement with the friction element 54 while the elements are traversing along the path for the articles.

To complete the self-contained unit, a drive sprocket 56 is rotatably supported on the top plate 42 (see FIG. 7) and releasably connected to the drive means 58 (to be described later).

The tension of the chain 34 is controlled by a shoe 60 (FIG. 4) engaging the peripheries of the respective rollers with the shoe 60 having pins 62 extending through a member 64 pivoted on a support (not shown) with the shoe being spring biased into engagement with the chain by springs 66. Additionally, the guide means or member 48 is adjustably connected to the upper and lower plates 42 and 44 by producing elongated slots 67 in the plates and connecting the guide member 48 to the plates through bolts 68 extending through the elongated slots and through openings in the guide member.

The attachment for the self-contained unit to the frame is more clearly shown in FIGS. 1, 5 and 6 and includes a pair of latch members 70 cooperating with bars 72 forming part of the frame 12 in a manner that the entire conveyor unit may be removed from the coating mechanism by mere manipulation of the latch members. Thus, as more clearly shown in FIG. 5, each latch member or means 70 includes-an element or latch 74 guided in a slot 76 formed between cooperating elements 78 which are fixed to the upper plate.42. The end of the latch 74 is adapted to be received in an opening 80 formed in the bar 72 and the latch or member 74 is held in the latched position by screws 82. The screws 82 extend through an elongated slot 84 formed in the member 74' to accommodate relative movement between the screws and the member. Thus, to

release the unit from the frame, it is only necessary to loosen four screws 82 and to slide the latch 74 to its retracted position.

The remaining mechanism for completing the conveyor construction includes means for maintaining continuous contact between an edge of an article fed to the path and an adjacent pair of rollers on the conveyor chain 34. This means is most clearly illustrated in FIG. 4 and includes a backing member 90 located on the opposite side of the path of movement of the articles and extending generally parallel to the flight 36.

The backing member 90 is in the form of a flat spring which is supported in a C-shaped element 92 extending along one side of the path and defining a slot 94 for receiving an edge of the article to be conveyed. As can be seen from an inspection of FIG. 4, the flat spring is supported in the C-shaped element 92 in a manner to form a cantilever extending across the slot 94. The C-shaped element 92, forming part of the frame 12, performs the additional function of preventing movement of the articles normal to the path of movement. Thus, it will be seen that the edge of the article is received in the slot and is supported on the rail defining the lower wall of the slot while the upper wall of the slot defined by another rail prevents upward movement.

The remaining means for supporting the articles includes a rail 96 connected to the lower plate 44 of the self-contained unit for supporting the opposite side of the article. In addition, a lug 98 (FIGS. 3 and 4) is secured to each of the links 40 interconnecting the adjacent pairs of rollers receiving the articles so as to completely restrict the movement of the articles in a direction normal to the path. Thus, it will be seen that the C-shaped element 92 defines upper and lower rails restricting movement of one end of the article 30 while the rail 96 and the lug 98 restrict the opposite end of the article.

The ends 30 are fed to the path, located between the backing member and the chain flight 36 by a suitable commercially available mechanism which locates an article or end in the path of periphery of the rollers in timed relation to the continuous movement of the chain 34. By way of example, the lower end 30 may be separated from the stack 32 and then suitable fingers push the end to a location substantially as shown at 30a in FIG. 3 where the next successive roller moving into the flight 36 will engage the edge of the end. The flat spring 90 then forces the edge of the end or article into constant engagement with the periphery of the adjacent pairs of rollers located on opposite sides of the lug 98. To insure sufficient frictional contact between the periphery of the rollers and the edge of the ends, the backing member or spring bar 90 is spaced from the periphery of the rollers by a dimension less than the diameter of the articles to be conveyed so that the spring bar must be deflected. With this arrangement, the spring bar 90 produces a force on the articles directed towards the rollers and thereby acts as a friction surface producing rolling contact between the edge of the article 30. To further insure sufl'icient contacting force between the periphery of the rollers and the edge of the articles, the backing memberor friction surface 54 is located on the opposite side of the periphery of the rollers requiring the rollers to be forced into engagement therewith and insuring rotation of the rollers.

The illustrated drive means 58 (FIG. 7) for the driven sprocket 56 may take any suitable form and in the illustrated embodiment includes a shaft 100 having a sprocket 102 thereon driven by a suitable source (not shown). The shaft 100 is connected to the sprocket 56 through a well known quick release connection 104 with a right angle gear 106 interposed between the sprocket 56 and the shaft 100. Thus, the drive mechanism may be readily disconnected from the driven sprocket 52 by merely releasing the coupling 104.

According to a further aspect of the present invention, the pattern of spray 24 produced by the spray heads 22 is restricted to a location between the backing member 90 and the flight 36 of the conveyor 34. Preferably, the pattern of spray 24 is substantially rectangular in form and has one dimension which is equal to or greater than the diameter of the articles to be coated while the second dimension is substantially less than the diameter. With this arrangement, the spray pattern can be centered on the path of movement, and the simultaneous rotation and longitudinal movement of the articles through the spray pattern will completely cover a surface of the article producing a coating which is devoid of streaks.

The method of coating articles utilizing apparatus of the present invention will now be briefly described. Circular disc like articles are sequentially removed from the stack 32 and are fed to a path of movement for the articles. When the articles reach the path extending through the spraying station, the articles are contacted at peripherally spaced locations on one side of the path by a pair of rotating continuously moving elements which are spaced a distance substantially less than the diameter of the articles. The opposite edge of the article is engaged with a stationary backing member to force the edge of the article or end into tangential contact with the two rotating elements so that the rotating elements cooperate with the backing member to move the article along the path and simultaneously rotate the article relative to the path.

A continuous pattern of spray of substantially rectangular configuration is produced transversely of the path with the length of the rectangular pattern being substantially greater than the diameter of the articles while the width thereof is substantially less. With this arrangement, the spray pattern can be located to prevent any direct spraying of any components of the conveyor. As is clearly shown in FIG. 4, the conveyor and backing member define a path therebetween and a void space beneath said path. Thus, an accumulation of spray on any supporting surface is impossible and one of the primary objectives of the invention is accomplished.

During the movement of the articles through the spraying station, the C-shaped element 92 and the rail 94 as well as the lug 98 will cooperate to restrain movement of the articles normal to the path. In addition, any localized build up of spray or coating which may be transferred to the periphery of the rollers from the edge of the ends will be dispersed by producing continuous rolling contact between the surface 50 as well as the surface on the friction plate 54 so that these surfaces will combine to define a wiper means to prevent accumulation of fluid material on the rollers.

As will be appreciated, the present invention provides a simple and inexpensive mechanism for continuously coating articles or ends to produce superior coating on the surface of the articles. Stated another way, by simultaneous rotation and continuous longitudinal movement of the articles across a pattern of spray coating, any streaking of the coating is substantially eliminated and the amount of excessive coating applied to the articles is considerably reduced. An additional advantage of the present system is that it eliminates the'complicated mechanism and controls for starting and stopping the movement of the articles as well as the spraying of the articles at a particular station. The particular arrangement as can be seen allows for continuously producing spray patterns of coating material and sequentially moving the articles under the spray pattern.

What is claimed is:

l. A device for coating flat, thin, disc-like articles comprising:

a frame structure;

a conveyor connected to said frame structure and having an endless chain with spaced rollers interconnected by links, said chain having one flight used for conveying articles;

a supportive elongated backing member connected to said frame structure and extending parallel to said flight along the entire conveying length thereof and spaced therefrom a distance substantially equal to the diameter of said articles, said conveyor and said backing member defining a path therebetween for said articles and a void space beneath said path;

means for sequentially feeding articles between said member and said flight until an edge of said articles engages said member and an adjacent pair of said rollers;

at least one spray head connected to said frame structure and positioned adjacent said path, said head being directed toward said path, said void space extending thereunder beneath said path to avoid accumulation of spray in said path; and

means for driving said chain to simultaneously rotate said articles along said path through a pattern of spray from said spray head, said pattern being directed solely between said backing member and said conveyor.

2. The device as defined in claim 1, further including means below said path along the edges thereof for supporting said articles.

3. The device as defined in claim 2, further including means above said path along the edges thereof for maintaining said 4. The device as defined in claim 1, including the further improvement of wiper means cooperating with said rollers to prevent accumulation of fluid material on said rollers.

5. The device as defined in claim 4, in which said wiper means comprises a guide surface for said chain on one end of said flight.

6. The device as defined in claim 1, in which said pattern of spray is substantially rectangular and has one dimension greater than the diameter of said articles and a second dimension substantially less than said diameter.

7. The device as defined in claim 1 wherein a plurality of spray heads are connected to said frame structure.

8. In combination with at least one spray head producing a pattern of spray, a conveyor for conveying substantially flat circular articles through said spray and comprising an endless chain having spaced rollers interconnected by links with a flight of said chain extending along one side of said pattern of spray; an elongated backing member extending along an op-. posite side of said pattern of spray and substantially parallel to said flight; means for sequentially feeding articles between said member and said flight with an edge of said articles engaging said member and an adjacent pair of rollers; means for driving said chain to simultaneously rotate and move said articles along a path through said pattern of spray; a self-contained unit including upper and lower plates with first and second spaced guide means interposed between said plates, said chain being entrained around said guide means; a drive sprocket engaging said chain and supported by one of said plates; and means defining a quick release connection between said drive means and said sprocket and said frame and said unit whereby said unit may be rapidly replaced.

9. In combination with at least one spray head producing a pattern of spray, a conveyor for conveying substantially flat, circular articles through said spray and comprising an endless chain having spaced rollers interconnected by links with a flight of said chain extending along one side of said pattern of spray; an elongated backing member extending along an opposite side of said pattern of spray and substantially parallel to said flight, said backing member comprising a flat spring supported adjacent said path to form a cantilever; means for sequentially feeding articles between said member and said flight with an edge of said articles engaging said member and adjacent pairs of rollers; and means for driving said chain to simultaneously rotate and move said articles along a path through said pattern of spray.

10. The combination as defined in claim 9, and further including an elongated substantially C-shaped element extending along said opposite side of said path and defining a slot for receiving an edge of said article, said flat spring being supported within said element and extending across said slot whereby said element prevents movement of said articles normal to said path.

* I: 3 III l 

1. A device for coating flat, thin, disc-like articles comprising: a frame structure; a conveyor connected to said frame structure and having an endless chain with spaced rollers interconnected by links, said chain having one flight used for conveying articles; a supportive elongated backing member connected to said frame structure and extending parallel to said flight along the entire conveying length thereof and spaced therefrom a distance substantially equal to the diameter of said articles, said conveyor and said backing member defining a path therebetween for said articles and a void space beneath said path; means for sequentially feeding articles between said member and said flight until an edge of said articles engages said member and an adjacent pair of said rollers; at least one spray head connected to said frame structure and positioned adjacent said path, said head being directed toward said path, said void space extending thereunder beneath said path to avoid accumulation of spray in said path; and means for driving said chain to simultaneously rotate said articles along said path through a pattern of spray from said spray head, said pattern being directed solely between said backing member and said conveyor.
 2. The device as defined in claim 1, further including means below said path along the edges thereof for supporting said articles.
 3. The device as defined in claim 2, further including means above said path along the edges thereof for maintaining said
 4. The device as defined in claim 1, including the further improvement of wiper means cooperating with said rollers to prevent accumulation of fluid material on said rollers.
 5. The device as defined in claim 4, in which said wiper means comprises a guide surface for said chain on one end of said flight.
 6. The device as defined in claim 1, in which said pattern of spray is substantially rectangular and has one dimension greater than the diameter of said articles and a second dimension substantially less than said diameter.
 7. The device as defined in claim 1 wherein a plurality of spray heads are connected to said frame structure.
 8. In combination with at least one spray head producing a pattern of spray, a conveyor for conveying substantially flat circular articles through said spray and comprising an endless chain having spaced rollers interconnected by links with a flight of said chain extending along one side of said pattern of spray; an elongated backing member extending along an opposite side of said pattern of spray and substantially parallel to said flight; means for sequentially feeding articles between said member and said flight with an edge of said articles engaging said member and an adjacent pair of rollers; means for driving said chain to simultaneously rotate and move said articles along a path through said pattern of sPray; a self-contained unit including upper and lower plates with first and second spaced guide means interposed between said plates, said chain being entrained around said guide means; a drive sprocket engaging said chain and supported by one of said plates; and means defining a quick release connection between said drive means and said sprocket and said frame and said unit whereby said unit may be rapidly replaced.
 9. In combination with at least one spray head producing a pattern of spray, a conveyor for conveying substantially flat, circular articles through said spray and comprising an endless chain having spaced rollers interconnected by links with a flight of said chain extending along one side of said pattern of spray; an elongated backing member extending along an opposite side of said pattern of spray and substantially parallel to said flight, said backing member comprising a flat spring supported adjacent said path to form a cantilever; means for sequentially feeding articles between said member and said flight with an edge of said articles engaging said member and adjacent pairs of rollers; and means for driving said chain to simultaneously rotate and move said articles along a path through said pattern of spray.
 10. The combination as defined in claim 9, and further including an elongated substantially C-shaped element extending along said opposite side of said path and defining a slot for receiving an edge of said article, said flat spring being supported within said element and extending across said slot whereby said element prevents movement of said articles normal to said path. 